Seals are used in an aircraft engine to isolate a fluid from one or more areas/regions of the engine. For example, seals are used to control various characteristics (e.g., temperature, pressure) within the areas/regions of the engine and ensure proper/efficient engine operation and stability.
Brush seals are a type of seal used to provide for fluid isolation in the manner described above. A brush seal may be implemented as a bundle/package of bristles sandwiched between two plates. Conventionally, the brush seal is manufactured with a plurality of wires/bristles, where each bristle is typically of the same size or diameter (disregarding any potential differences due to tolerances in manufacture of the bristles). Generally, smaller diameter bristles provide for better sealing capability. But, such enhanced sealing capability comes at the expense of a loss of strength.
Due in part to recent developments in engine design, engines are trending towards increased operating temperatures and pressures. At elevated temperatures (e.g., temperatures above a threshold amount), the seal experiences a loss of material properties/capabilities. If the seal is exposed to increased pressure/pressure drop (e.g., a pressure or pressure drop greater than a threshold) the seal's “blow-over capability” or ability to withstand load can be compromised.
What is needed is an improved brush seal that is better suited to operate in engine environments characterized by high temperature and high pressure.